Jan Kok wrote: > Indeed, I was about to recommend LTSpice/SwCAD III as well. I assume > it's the same software that Ian mentioned. > http://www.linear.com/designtools/software/switchercad.jsp > > It's free (as in beer), and easy to use, after you spend a few hours > reading the tutorial.
Thanks Guys (Jan and Ian), that got me going and I'm simulating now. > Unless Ian or someone can post instructions about how to import the > eschema netlist into LTSpice, I wouldn't bother trying. Just re-enter > the schematic into LTSpice using their schematic editor. That's the > easy part. Yup. > The harder part is creating models of components that > aren't in the LTSpice library, Yes, Toshiba isn't nice about offering SPICE models of their jFETs and same with Supertex in that I happen to want to use some components that they don't have models for yet. http://www.supertex.com/spice_models.html I'll have to read-up on how to make my own models from the datasheet info. Any pointers how to do it? This is new to me :) > creating stimulii waveform sources for > your circuit, adding in parasitic resistances, capacitances, and > inductances into your circuit as needed to get the simulation to run > and produce realistic results. ("Parasitic" components are the ones > you don't show on a normal schematic but which are there in real life > and sometimes affect circuit operation. For example, resistance in PCB > traces, inductance in transistor leads.) That part I can't fully imagine, but the stray stuff I'm not interested in at the moment. What I am trying to do is model why my circuit is so sensitive to power supply ripple. It's a 100-watt all FET (mos and j) power amplifier that uses just 10 devices. At first, I thought it was matching transconductance of the front-end jFETs, but doesn't appear to be the case. The mixing in the driver stage should cancel but isn't for an unknown reason. And that's why I'm here.. soldering just sucks :) I have the voltage sources set for +/-54V with a 4mV sinewave ripple (should be saw, but I'm fine with that), and I do get ripple on my output just like the real circuit, so I guess the model is accurate to my needs. Next is changing around parts and values 'till I find the proper cancel. Is there a way to do batch and compare with LTSpice such that I can modify a part value within a range, sim all results, and compare what I got in a graph? -- You know, Hobbes, some days even my lucky rocketship underpants don't help. -- Calvin
